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			<h1>Tape.java</h1>
			<p>Written in <span title="Programming 2">CS 1103</span> of <a href="http://www.uopeople.edu/">University of the People</a>, finalised on 2017-07-05</p>
		</header>
<h2>Source code:</h2>
<blockquote>
<pre><code>/* 
 * Copyright (C) 2017 Alex Yst
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see &lt;http://www.gnu.org/licenses/&gt;.
 */
package turing;

/**
 * Alex Yst&apos;s CS 1103 (Programming 2) Unit 3 submission
 * 
 * This class represents a tape of unlimited cells. A single cell exists in
 * memory to begin with, but more are added as needed.
 * 
 * @author Alex Yst
 */
public class Tape {
/**
 * This is the current working cell. All operations are performed in the
 * context of this cell.
 */
	private Cell currentCell;
/**
 * This is the cell at the &quot;beginning&quot; of the tape.
 */
	private Cell beginning;
/**
 * This method should usually never be needed. It returns the current working
 * cell, and with it, the whole known section of the tape. Use this method with
 * care.
 * 
 * @return The current working cell
 */
	public Cell getCurrentCell() {
		return currentCell;
	}
/**
 * This method returns the character content of the current working cell.
 * 
 * @return The content of the current working cell
 */
	public char getContent() {
		return currentCell.content;
	}
/**
 * This method sets the character of the current working cell.
 * 
 * @param ch The character to set
 */
	public void setContent(char ch) {
		currentCell.content = ch;
	}
/**
 * Sets the new current working cell to be the cell previous of the current
 * current working cell, adding a cell if need be.
 */
	public void moveLeft() {
		if(currentCell.prev == null) {
			currentCell.prev = new Cell();
			currentCell.prev.next = currentCell;
			currentCell.prev.content = &apos; &apos;;
			beginning = currentCell.prev;
		}
		currentCell = currentCell.prev;
	}
/**
 * Sets the new current working cell to be the cell after of the current
 * current working cell, adding a cell if need be.
 */
	public void moveRight() {
		if(currentCell.next == null) {
			currentCell.next = new Cell();
			currentCell.next.prev = currentCell;
			currentCell.next.content = &apos; &apos;;
		}
		currentCell = currentCell.next;
	}
/**
 * This method returns the contents of the known section of the tape, in string
 * form.
 * 
 * @return The known contents of the tape
 */
	public String getTapeContents() {
		String s = &quot;&quot;;
		Cell current = beginning;
		while(current != null) {
			s += current.content;
			current = current.next;
		}
		return s;
	}
/**
 * Constructor method. Just sets the default state of the tape to something
 * sensible.
 */
	public Tape() {
		currentCell = new Cell();
		currentCell.content = &apos; &apos;;
		beginning = currentCell;
	}
}</code></pre>
</blockquote>
<h2>Test output:</h2>
<h3><code>TestTape.java</code>:</h3>
<blockquote>
<pre><code>Tape Conents:  Hello World 
Final position at the W</code></pre>
</blockquote>
<h3><code>TestTapeGUI.java</code>:</h3>
<img src="/y.st./source/y.st./static/img/CC_BY-SA_4.0/y.st./coursework/CS1103/Type.java.png" alt="Test Tape" class="weblog-header-image" />
<h3><code>TestTuringMachine.java</code>:</h3>
<blockquote>
<pre><code>Running machine #1.  Output should be:  Hello
Actual output is:                       Hello 

Running machine #2.  Should throw an IllegalStateExcpetion.
Caught Illegal Argument Exception, with error message:
Cannot find an applicable rule; tape contents =  ERROR

Running machine #3.  Output should be: aababbbababbabbaba aababbbababbabbaba
Actual output is:                      aababbbababbabbaba aababbbababbabbaba</code></pre>
</blockquote>
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			Copyright © 2017 Alex Yst;
			You may modify and/or redistribute this document under the terms of the <a rel="license" href="/license/gpl-3.0-standalone.xhtml"><abbr title="GNU&apos;s Not Unix">GNU</abbr> <abbr title="General Public License version Three or later">GPLv3+</abbr></a>.
			If for some reason you would prefer to modify and/or distribute this document under other free copyleft terms, please ask me via email.
			My address is in the source comments near the top of this document.
			This license also applies to embedded content such as images.
			For more information on that, see <a href="/en/a/licensing.xhtml">licensing</a>.
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